Electromechanical actuator having control and drive circuit

Abstract

An electromechanical actuator includes an electric motor and a control and drive circuit mounted integrally with the electric motor. The control and drive circuit includes a serial-to-parallel converter for converting a control signal in the form of serial data into parallel data, and a device responsive to the control signal in the form of parallel data for producing a drive current or voltage for the electric motor. A system for accessing or controlling a plurality of such actuators by commands from a main controller can include a control and drive circuit which is integral with the motor itself.

What is claimed is: 
     
       1. An actuator control system comprising: an electromechanical actuator including an electric motor, and a control and drive circuit mounted integrally with said electric motor;   a controller for controlling said electromechanical actuator, said controller supplying a control signal in the form of serial data to said control and drive circuit of said electromechanical actuator, said control signal commanding the amount of rotation of said electric motor;   said control and drive circuit comprising a serial-to-parallel converter fro converting said control signal in the form of serial data into parallel data, a timing-control circuit fed by said serial-to-parallel converter, said timing-control circuit being responsive to said parallel data from said serial-to-parallel converter for producing a drive signal for controlling the timing of operation of said electric motor, a drive circuit fed by said timing-control circuit and responsive to said drive signal for producing a drive current to said electric motor, said timing control circuit producing, upon completion of rotation of said electric motor through the commanded amount of rotation, a completion signal as parallel data for indicating completion of said commanded amount of rotation, and a parallel-to-serial converter receiving said completion signal as said parallel data from said timing-control circuit for converting said parallel data into serial data and supplying said serial data to said controller.   
     
     
       2. A system as set forth in claim 1, wherein said motor has a stator winding, and a metal plate surrounding said stator winding to form part of a stator of said motor, and said control and drive circuit is mounted on said metal plate. 
     
     
       3. A system as set forth in claim 2, wherein said control and drive circuit is in the form of an integrated circuit chip secured to said metal plate. 
     
     
       4. A system as set forth in claim 2, wherein said metal plate forms at least part of a path for the magnetic flux created by said stator winding. 
     
     
       5. A system as set forth in claim 2, wherein said control and drive circuit is disposed inside metal plate. 
     
     
       6. A system according to claim 1, wherein said drive circuit includes a plurality of switching elements which are selectively turned on and off responsive to said drive signal to control the current to said electric motor. 
     
     
       7. A system according to claim 1, wherein said drive signal produced by said timing control circuit is maintained in an active state until said electric motor rotates the commanded amount. 
     
     
       8. A system according to claim 1, wherein said controller is responsive to said serial data supplied from said parallel-to-serial converter for performing control of said electric motor for a subsequent motor operation.